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Nano-Micro Letters 2011年第2期3卷 108-114页

作者： Z.Durmus h.Sozeri M.S.Toprak A.Baykal Department of Chemistry Fatih University TUBITAK-UME National Metrology Institute Functional Materials Division Royal Institute of Technology-KTH

We present a comparison for the effect of condensation on the morphology and magnetic prop erties of oleic acid modified BaFe_(12)O_(19) *** different samples of BaFe_(12)O_(19) nanoparticles were synthesized by dehydration(Z1) and rotary evaporation(Z2) method,*** acid was used as the surface modification agent to observe the morphological and magnetic *** nanoparticles were analyzed by XRD,FTIR,TGA,SEM,and VSM techniques for structural and physicochemical characteris *** analysis reveals the phase as hexaferrite and the average crystallite size of Z1 and Z2 is 21±3 nm and 17±2 nm,*** evaporator accelerates the condensation process in viscous gel(Z2).Due to the use of rotary evaporator,the coating with oleic acid for Z2 product has been accomplished very well,as compared with *** a result,saturation magnetization of Z2 sample is much lower than that of Z1 sample.

关键词： BaFe12O19 Nanoparticles Rotary evaporatory Condensation Magnetic properties

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A NOTE ON CONTINUATION AND BOUNDEDNESS OF SOLUTIONS OF A NONLINEAR DIFFERENTIAL EQUATION

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Acta Mathematica Scientia 1984年第3期4卷 259-264页

作者： h.EL-OW AIDY,A.S.ZAGROUT Math. Dept. Faculty of Science King Abdul Aziz University Jaddah SAUDI ARABIA Math. Dept. Faculty of Science King Abdul Aziz University Jaddah SAUDI ARABIA

A nonlinear second order differential equation is considered. Sufficient conditions for all solutions to be continuable and bounded to the right of an initial value t0≥0 are given.

关键词： A NOTE ON CONTINUATION AND BOUNDEDNESS OF SOLUTIONS OF A NONLINEAR DIFFERENTIAL EQUATION

On the mechanism and control for the ultra-low frequency oscillation in NY Power Grid with large-scale hydropower

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Control Theory and Technology 2019年第3期17卷 241-251页

作者： Ancheng XUE Jiawei WANG Chao ZhENG Joe h.ChOW Tianshu BI State Key Laboratory of Alternate Electrical Power System with Renewable Energy Source (North China Electric Power University) Changping District Beijing 102206 China China Electric Power Research Institute Haidian District Beijing 100192 China Department of Electrical Computer and Systems Engineering Rensselaer Polytechnic Institute Troy 12180 New York State U.S.A.

The power grid with large proportion of hydropower may engage the ultra-low frequency oscillation (ULFO),which threatening the operation of *** the NY Power Grid system,whose dimension is over thousands,this paper reveals the cause of ULFO with the phase portrait method,i.e.,lies in the saturation of the different limits of the governor system of the generators,in other words,the occurrence of limit cycle is due to the non-smooth *** furthermore,it proposes two methods to suppress ULFO with the philosophy of destroying the condition of non-smooth *** detail,first,the phenomenon of ULFO in NY Power Grid,the damping characteristics and the limits in the governor system of the hydropower units are ***,based on the non-smooth bifurcation theory,the mathematical basis of the oscillation in the non-smooth system caused by the saturation of limits is *** then,the non-oscillation and oscillation dynamic of the system corresponding to without/with limits in the governor system are ***,it discusses the influence of the saturation of single limit on the characteristics of ULFO with the phase ***,the phase portraits of the ULFO under different faults is analyzed,and it shows that the limiting saturation occurs with a large enough ***,the ULFO is resulting from the negative damping of generation and the saturation of multiple limits under a large enough *** addition,according to the above mechanism,two strategies to suppress the ULFO,i.e.,the governor parameters tuning and the fault strength relief are *** simulation shows the effectiveness of proposed strategies.

关键词： Ultra -low frequency oscillatio n gover nor system limit no rnsmooth bifurcation limit cycle

STUDY ON CRYOGENIC PhASE ChANGE & WEAR ChARACTERISTIC OF hIGh SPEED STEEL

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Acta Metallurgica Sinica(English Letters) 2003年第6期16卷 524-530页

作者： M.C.huang C.h.Gao L.G.huang DepartmentofMechanicalEngineering FuzhouUniversityFuzhou350002China hefeiUniversityofTechnology Hefei230009China

The microscopic structure change rule in high speed steel (hSS) after an additional cryogenic treatment was studied in this paper. highly dispersed nano-carbide (η-Fe2 C) separated from tempering martensite was found distributed on twin planes of marten-site and dislocation places. Retained austenite was found sheared into martensite and nano-carbide separated at the same time. In addition, the tempering martensite was fine-grained. The stated changes of hSS evidently improve the lifespan of hSS cutter and fully show the advantages of nano-structure. The cryogenic treatment of hSS also improves the roughness of hSS cutter (decrease Ra number by about 50%) and greatly increases the wear resistance of hSS cutter. Further experiments on the wear characteristic of hSS cutter supported the findings mentioned above. The stated hSS treatment technology would implement nano-structure of traditional tool steel through phase change. It could be a new method to improve the performance of hSS cutter.

关键词： high speed steel cryogenic treatment phase change wear char-acteristic nano-structure

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Effects of 4-hexylresorcinol on the phenoloxidase from hyphantria cunea （Lepidoptera： Arctiidae）： In vivo and in vitro studies

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Insect Science 2015年第5期22卷 639-650页

作者： Mahboobeh Sharifi Mohammad Ghadamyari Reza h. Sajedi Nosrat O. Mahmoodi Department of Plant Protection Faculty of Agricultural Sciences University of Guilan Rasht Department of Biochemistry Faculty of Biological Sciences Tarbiat Modares University Tehran and Department of Chemistry Faculty of Sciences University of Guilan Rasht Iran

Insecticidal effects of 4-hexylresorcinol, a phenoloxidase （PO） inhibitor, were determined on hyphantria cunea （Drury） under laboratory conditions. The LC50 for the 15- d-old larvae was estimated to be 2.95 g/L after 96 h exposure. The activities of glutathione S-transferase （GST） and PO showed a decrease in larvae treated with 4-hexylresorcinol, and the IC50 of GST and PO were estimated to be 0.8 and 0.43 g/L, respectively, 24 h after treatment. The PO from the hemolymph of fall webworm was purified by ammonium sulfate precipitation, gel-filtration, and ion-exchange chromatography, and then enzymatic characteristics and the mechanism of inhibition were determined using L-dihydroxyphenylalanine （L-DOPA） as the substrate. The purified PO showed a single band on SDS-PAGE with a molecular weight of about 70 kDa. The optimum ph for PO activity was observed at ph 7.0, optimum temperature was found to be 45 ℃, and PO activity was strongly inhibited by Zn2＋. IC50 values were estimated to be 8.2, 19.14, and 24.04/zmol/L for 4-hexylresorsinol, kojic acid, and quercetin, respectively. The inhibitory potencies （i.e., 150 of each compound/Is0 of 4-hexylresorcinol） ofkojic acid and quercetin on h. cunea PO were estimated to be 1.87 and 2.89, respectively. 4-hexylresorcinol was determined to be a competitive inhibitor, and kojic acid and quercetin were determined to be mixed inhibitors. PO is one of the most important enzymes in an insect＇s immune system, and the use ofPO inhibitors seems to be a promising approach for pest control due to their potential safety for humans.

关键词： 4-hexylresorcinol hyphantria cunea IC5o inhibition mechanisms LCso phenoloxidase

EXPERIMENTAL RESEARCh AND NUMERICAL SIMULATION OF MOLD TEMPERATURE FIELD IN CONTINUOUS CASTING OF STEEL

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Acta Metallurgica Sinica(English Letters) 2006年第3期19卷 176-182页

作者： X.S. Zheng M.h. Sha J.Z. Jin Research Center of Foundry Engineering Dnlian University of Technology Dalian 116024 China School of Materials Science and Engineering Anshan University of Science and Technology Anshan 114044 China

Mold is the heart of the continuous casting machine. heat transfer and solidification in a water- cooled mold are the most important factors during the continuous casting of steel. For studying the temperature distribution of a mold wall, a simulated apparatus of mold was designed and experiments were performed by it. The measured results indicated that the mold wall temperature approaches the temperature of cooling-water. An equivalent thermal-conductivity coefficient was proposed and deduced on the basis of the conclusion of the experiments. This coefficient was applied to solve the heat transfer between the melt and cooling water, and to characterize the heat transfer capacity of the mold. By this equivalent thermal-conductivity coefficient, it is very easy and convenient to numerically simulate the solidification process of continuous casting. And the calculation results are in agreement with the experiments. The effects of custing speed and water flow rate on the mold temperature field were also discussed.

关键词： continuous casting mold temperature field numerical simulation

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Small-signal Angular Stability of Power System as Affected by Grid-connected Variable Speed Wind Generators—A Survey of Recent Representative Works

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CSEE Journal of Power and Energy Systems 2017年第3期3卷 223-231页

作者： Wenjuan Du Jingtian Bi h.F.Wang State Key Laboratory of Alternate Electric Power Systems(SKLAEPS)with New Energy Resources North China Electric Power UniversityBeijing 102206China

This paper reviews the status and progress of the investigation on power system small-signal angular stability as affected by grid-connected variable speed wind generators(VSWGs).The review is carried out on the basis of a survey of recently published representative *** of the investigation made in those selected papers are classified into two groups:1)VSWGs displacing synchronous generators(SGs);2)VSWGs simply being added in a power *** diversification of the results of the investigation is highlighted in the *** analysis on two strategies of the investigation is conducted in this *** is revealed that in the strategy of VSWGs displacing SGs,there are two factors which could affect power system small-signal angular stability differently:1)Withdrawing the SGs’dynamics;2)adding the VSWGs’*** the strategy of adding VSWGs in the power system,there are also two affecting factors:1)Change of load flow brought about by the VSWGs;2)dynamic interactions with the SGs introduced by the *** diversified results of the investigation obtained so far are not only due to the dependence of the investigation on sample power systems used,but also caused by the mixture of different affecting *** paper is concluded with a summary of key issues of the investigation for future work.

关键词： Electromechanical oscillation modes power system dynamics power system low-frequency oscillation power system small-signal angular stability synchronous generators(SGs) variable speed wind generators(VSWGs)

Structural biology of the macroautophagy machinery

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Frontiers in Biology 2014年第1期9卷 18-34页

作者： Leon h. ChEW Calvin K. YIP Department of Biochemistry and Molecular Biology The University of British Columbia 2350 Health Sciences Mall Vancouver BC V6T1Z3 Canada

Macroautophagy is a conserved degradative process mediated through formation of a unique double- membrane structure, the autophagosome. The discovery of autophagy-related （Atg） genes required for autophagosome formation has led to the characterization of approximately 20 genes mediating this process. Recent structural studies of the Atg proteins have provided the molecular basis for their function. here we summarize the recent progress in elucidating the structural basis for autophagosome formation.

关键词： macroautophagy autophagy Atg proteins structural biology X-ray crystallography single-particle electronmicroscopy

The immunology of human cytomegalovirus latency： could latent infection be cleared by novel immunotherapeutic strategies？

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Cellular & Molecular Immunology 2015年第2期12卷 128-138页

作者： Mark R Wills Emma Poole Betty Lau Ben Krishna John h Sinclair Department of Medicine University of Cambridge Cambridge UK

While the host immune response following primary human cytomegalovirus （hCMV） infection is generally effective at stopping virus replication and dissemination, virus is never cleared by the host and like all herpesviruses, persists for life. At least in part, this persistence is known to be facilitated by the ability of hCMV to establish latency in myeloid cells in which infection is essentially silent with, importantly, a total lack of new virus production. however, although the viral transcription programme during latency is much suppressed, a number of viral genes are expressed during latent infection at the protein level and many of these have been shown to have profound effects on the latent cell and its environment. Intriguingly, many of these latency-associated genes are also expressed during lyric infection. Therefore, why the same potent host immune responses generated during lytic infection to these viral gene products are not recognized during latency, thereby allowing clearance of latently infected cells, is far from clear. Reactivation from latency is also a major cause of hCMV-mediated disease, particularly in the immune compromised and immune naive, and is also likely to be a major source of virus in chronic subclinical hCMV infection which has been suggested to be associated with long-term diseases such as atherosclerosis and some neoplasias. Consequently, understanding latency and why latenUy infected cells appear to be immunoprivileged is crucial for an understanding of the pathogenesis of hCMV and may help to design strategies to eliminate latent virus reservoirs, at least in certain clinical settings.

关键词： Cytomegalovirus latency immune evasion immunotherapeutic

RESTORATION OF SUPPRESSED IMMUNITY IN BURNED MICE WITh CIMETIDINE

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中华医学杂志(英文版) 1985年第5期98卷 384-387页

作者： R Zapata-Sirvent JF hansbrough V Peterson h Claman Burn and Trauma Research Laboratory Department of Surgery University of Colorado Health Sciences Center Denver CO China

Thermal injury has been shown to result in suppression of many aspects of immunity. We studied the effect of cimetidine on suppressed cell mediated immunity in burned mice, utilizing a method of quantitating sensitivity to the contact antigen, 2,4-dinitrofluorobenzene. Daily administration of cimetidine resulted in maintenance of normal cell mediated immunity in these otherwise immunosuppressed animals. This effect may be secondary to the antagonism of cimetidine with histamine h2receptors on suppressor cells. Immunorestoration with cimetidine may improve resistance of the burned host to infectious complications.

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